The **W2PA-1GF-R2/Q** is a high-precision RF (Radio Frequency) probe head assembly typically manufactured by **Cascade Microtech** (now part of **FormFactor**). These components are essential in the semiconductor testing industry, specifically for Wafer-Level Reliability (WLR) and high-frequency characterization. --- ### 1. Technical Specifications The "W2PA" series usually refers to a specific configuration of the **ACP (Analytical Ceramic Point)** or similar probe lines designed for high-performance probing. | Feature | Description | | :--- | :--- | | **Probe Type** | GSG (Ground-Signal-Ground) or GS (Ground-Signal) | | **Pitch** | Variable (often 100µm to 250µm) | | **Frequency Range** | Typically DC to 40 GHz / 67 GHz (depending on exact sub-model) | | **Connector Type** | Usually 2.92mm (K) or 1.85mm (V) female | | **Material** | Tungsten or Beryllium Copper (BeCu) tips | --- ### 2. Breakdown of the Part Number While specific internal manufacturer codes may vary, the nomenclature generally follows this logic: * **W2PA:** The series identifier, indicating the mechanical housing and probe family (often associated with **WinCal** calibration compatibility). * **1GF:** Likely refers to the **1 GHz to 40/67 GHz** performance tier or a specific "General Frequency" calibration standard. * **R2:** Indicates the revision of the mechanical design or a specific radius/reach configuration. * **Q:** Often stands for **Quadrant** or a specific mounting orientation for multi-probe stations. --- ### 3. Key Electronic Functions The W2PA-1GF-R2/Q serves as the interface between high-end test equipment (like a Vector Network Analyzer - VNA) and the microscopic pads on a silicon wafer. 1. **Impedance Matching:** Maintains a strict **50 Ohm** environment from the coaxial cable down to the probe tip to prevent signal reflections. 2. **Low Insertion Loss:** Engineered to ensure minimal power loss during high-frequency signal transmission. 3. **Compliant Tips:** The "R2" design often includes a degree of mechanical flexibility (spring constant) to ensure stable electrical contact without damaging the fragile bond pads of the chip. 4. **Crosstalk Suppression:** The Ground-Signal-Ground architecture provides excellent electromagnetic shielding for sensitive RF measurements. --- ### 4. Common Applications * **RF Characterization:** Measuring S-parameters of transistors. * **Wafer-Level Testing:** Validating chips before they are packaged to save costs. * **Device Modeling:** Used by R&D engineers to create accurate software models of new semiconductor materials (GaN, SiC). ---